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The Ultimate Guide to Dewinterization

February 19, 2024by Peter Hudson

How to Turn Your Sprinkler System Back on After Winter

Sooner than later, it will be time for your sprinkler system to tackle once again the hottest of hottest days. With March and April ushering in the warmth, it’s time to awaken your sprinkler system and transform the yellow grass into a vibrant green. Dewinterization is the process of turning your system back on after winter, and it can be tricky if not done correctly. So here are some steps to properly turn your system back on:

  1. Locate Your Backflow

Your backflow plays an important role in ensuring the precise flow of water in one direction, keeping your home’s water supply from contamination.  When it comes to dewinterization, your focus will mostly be on the backflow system. The backflow should be located on the side of the house.

2. Take Off the Top and Check the Bonnet

First, take a pair of plyers and unscrew the top (which looks like a bell). Then, inspect the inside for leaks, which should include the bonnet, poppet, spring, and check valve. Examine the parts for any damage, and if you do see damage, stop working and give us a call.

3. Turn off the #1 Shut Off Valve

To turn off the #1 shut-off valve, which is located directly under the bell, take the handle, and rotate it until it is parallel to the ground. See picture below for example:

4. Turn on Isolation Valve

Locate the isolation valve, check either on the backflow preventer or in a green box near your water meter. To turn on the isolation valve, slowly turn the handle until it is parallel with the pipe.

5. Open #1 Shut off Valve

Now, it’s time to turn the #1 shut-off valve back on. To do this, take the handle and move it back to where it is parallel with the bell. See picture below for example:

6. Shut off Test Cocks

After re-opening shut off valve #1, use a flathead screwdriver to close your tests cocks to be in the same direction as the handles. See picture below for example of how the test cocks should look:

7. Turn on Shut Off Valve #2

To turn on shut off valve #2, take the handle on the valve and shift it to where it is parallel with the ground.


After turning on shut-off valve #2, you should be done. Note that there should be no water dripping from your backflow continuously. Run your system after completion to ensure everything is working properly. Your backflow should look like this after the de-winterization process. Southwest Irrigation Systems is here to help you in the dewinterization process if needed. Feel free to give us a call for any questions or to get scheduled for your dewinterization visit. 281-494-3700. For more about our sprinkler services check out: Sprinkler System Installation & Repairs

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